iOS 12.3 (build 16F5129d) is an official Apple over-the-air update for the iPhone 6s, released on 2019-04-08T17:05:11Z. The update package is 372.89 MB. This is a delta (partial) update that requires 12.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8ecffaa04ee822a838b49a08dbf2c27c874f3008.zip.